A bit old topic, but... I do not see anywhere mentioned "floating" element/s... from 2.5x to 5x lens extend... so, if elements inside do not move at all and lens keeps its focal length then this helicoid extension is for convenience only, instead of mounting it on bellows and extend it this way to ...

These are beautifully lit. Lovely photos!

Good choice, we will all miss Robert's posts from now on.

"....the supposedly exotic glass is just a marketing blurb." As I mentioned in the other thread, you have no evidence for that statement; quite the contrary. The lens had no detectable CA in the tests on that thread. Yes, it was not as sharp as the Laowa in that test, but if I recall correctly, it ...

Maybe I am misunderstanding what you mean by "autofocus". Do you want the lens to focus autonomously without human intervention? Or do you just want to be able to motorize the focus, which would be controlled by you through the motor? "In said cases, as when you're focus stacking for instance, my un...

"....the supposedly exotic glass is just a marketing blurb." As I mentioned in the other thread, you have no evidence for that statement; quite the contrary. The lens had no detectable CA in the tests on that thread. Yes, it was not as sharp as the Laowa in that test, but if I recall correctly, it w...

These are remarkable. Did you use 365nm light?

Hi and thank you for the quick replies 1. It will definitely work. And I would buy something like that - if price is right ;-) 2. Cheap M42 helicoids from China are widely available 3. I got one and mine makes 360 degrees turn for ~12.5 mm linear movement. 200 step/rev is 0.0625 mm... on your model...

I do this manually with a cine follow-focus attachment, and it works well. A motorized version of this would be very useful! But I find myself using this not only with helicoids but with regular macro lenses. I'd recommend not making the helicoid part of the system, but rather making your device so ...

The Mamiya "Z" lenses are the latest, designed for the RZ-67 (hence the "Z" in the lens name) instead of the RB-67. These two cameras differ in flange distance.

Lens chronology for the RB-67 is available here:
https://lens-db.com/system/mamiya-rb67/

Hmm, an extension ring will cause a similar problem as bellows, except for the lack of flexibility. If you want more magnification, I'd recommend using a 1.4x teleconverter. It will allow your lens to work as it should in terms of focal length and close range correction, while giving you a magnific...

Thank you so much, I really don't want to inconvenience you but that would be very helpful! Both those Mamiya lenses sound really great but I think I'd rather have the ability to use them short-focussed and/or bellows too (though mainly for full frame and bigger) - but I wonder how you mount them i...

Wonderful photos, as always! The feeding leech is especially remarkable! I've never seen that. I am confused about the ID. If I'm looking at the right photo, Paul calls it a "land planarian". But Wikipedia tells me that "leech" is phylum Annelida, while planarian is phylum Platyhelminthes. Visually...

That really is excellent!

The important thing here is the proven importance (now proven again) of maintaining the floating elements in their correct position for the desired magnification. This is a very general rule.